Valve for hammer-drills.



V..J. OBRIEN. VALVE FOR HAMMER DRILLS. APPLICATION FI ED MAY 14, 1909.

. Patented June 28, 1910.

4 SHEETS-SHEET 1.

v. J. O'BRIEN. VALVE FOR HAMMER DRILLS.

7 APPLICATION FILED MAY 14, 190 9. v v 962,717, Patented June 28, 1910.

4 SHEETSSHEET 2.

V. J. OBRIEN.

VALVE FOR HAMMER DRILLS.

APPLIOATION FILED MAY 14, 1909.

mm mm 3 66 m (R m I ii i TED "STATES PATENT ,oFF oE.

V'INGENT \T. OBRIEN, OF DENVER, COLORADO, ASSIGNOR OF ONE-THIRD TO ROMEOC. .A WKEREAN AN'D ONE-THIRD TO THOMAS PUNSHON, J R., F DENVER,COLORADO.

VALVE FOR HAMMER-DRILLS.

Specification of Letters Patent. Patented J une 2S, 1910.

Application filed May 14, 1909. Serial No. 496,078.

To all whom 'it may concern! Be it,-known that I, VINCENT J. QBnin v, a'citizen of-the United States, resldmg in the city and county of Denverand State of Colorado, have invented certain new and useful Improvementsin Valves for Hammer;Drills; and I do declare the following to be afull, clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame, reference being had to the accompanying drawings, and to thenumerals ofreference marked thereon, which form a part of thisspecification.

My invention 'relatesto improvements in valves for hammer drills, myobjectbeing to provide a valve which, while properly performing therequired function, shall be exceedingly durable.

My improved valve belongs to that class having differential pressureareas at its opposite extremities, the smaller of these. areasbeingconstantly exposed to the pressure of the live motive fluid, while theopposite or larger area, is intermittently exposed to the said fluid.Valves of this character as here tofore constructed have been supported,so

far as I am aware, by the surrounding walls of the valve chest alone andas these walls are grooved, the wear to which the external surface ofthe valve is subjected by virtue of coming in contact with the edges ofthese grooves, is so great that the valve is short lived and must befrequently replaced.

My object is to overcome this difiiculty, and to this end I equip thevalve chest with 'a cylindrical support which passes through the hollowcylinder valve and forms an internal support therefor. By virtue of thisconstruction the internal cylindrical core forms the support for thevalve and as this core, together withthe inner surface of thecylindrical valve, is practically smooth and unbroken by grooves, thevalve is to a large extent relieved from the wear incident to valves ofthis character under ordinary circumstances.

A further improvement consists in the are closed. Furthermore eachofthese pas sages is relatively small butthe' number of passages issufiicient to make up for the difference in the cross sectional area ofthe individual passages. By virtue of this construction the wear towhich the valve is subjected by the action of the motive fluid isgreatly reduced as compared with constructions having one or morerelatively'large passages for the performance of the aforesaid function.

Another featureofjny improvement consists in the fact that thevalve-supporting core is formed hollow and is in communication withexhaust passages vformed in the cylinder for the purpose of exhaustingthe motive fluid from the rear extremity of the piston chamber when thelatter is making its return or rearward stroke.

Having briefly outlinedvmy improved construction I will proceed todescribe the same in detail, reference being made to the accompanyingdrawing in which is illustrated an embodiment thereof.

In this drawing, Figure 1 is a side elevationillustrating a drill of thecharacter to which my improvements are applicable, the same being shownin use. Fig. 2 is a longitudinal section taken through the drillcylinder with the hammer, valve mechanism and striking piston shown inelevation, the

parts being shown on a larger scale. Fig. 3 is a cross section taken onthe-line 3-3, Fig.

2. Figs. 4, 5, 6 and 7 are longitudinal sec- I tions taken on the lines44t, 55, 66 and 7 7 respectively, of Fig. 10, the hammer, however, aswell as the valve, being shown in different positions. Fig. 8 is adetail view of the disk and the valve-supporting core formed i tegraltherewith, shown on a still larger scale. Fig. 9 is a detail view of thecylinder valve shown in elevation. Figs. 10 and 11 are sections taken onthe lines 10'1O and 1l11 respectively of Fig. 6. Fig. 12 is a sectiontaken on the line 12-12 of Fig. 4.

The same reference characters indicate the same parts in all the views.

- Let the numeral 5 designate the body of i the drill cylinder; 6 thepiston hammer; 7 the striking pin; 8 the valve chest; 9 the valveproper; 10 the valve-supporting core; and 11 the disk upon which thecore is mounted and with which it is formed in tegral.

The disk 11 is provided with intake ports 12' registering, with. intakepassages '13.,

formed in the valve chest and extending fora seat or stop for the valvewhen the latter is in its forward or closed position. The

- groove 15 is in, communication, when the valve is open, with a thirdgroove 16, from which lead intake passages 17 to the rear extremity ofthe hammer chamber. a I is open or in the position shown in Figs, f and5, the live Assuming that the valve motive fluid enters the rearextremity of the hammer chamber through the ports 12, the passages 13,the grooves 14:, 15 and 16, and

the passage 17 and acts to drive the hammer 6 forwardly against thestriking pin 7,

whose rear extremity protrudes into the for ward extremity of the hammerchamber.

Shortly before the hammer reaches its forward limit of movement, thelive air in the rear thereof exhausts through a port 18' communicatingwith a passage 19 formed in the casing 15 and in alinement with apassage 20 formed in the valve chest and communicating at its forwardextremity with a passage 21 leading to a space 22 in the rear of therear extremity of the valve. The area of the face 36 of the rear end ofthe valve is greater than the area of its opposite end,

hence the live air acting upon the greater area shifts the valve to itsforward or closed position (see Figs. 6 and 7). As soon as this occursthe live air from the groove 14: passes through a series of relativelysmall passages 25, having one extremity in communication with the liveair groove 14, while their opposite extremities are in communicationwith a circumferential, groove 26 formed in the valve chest andsurrounding the valve. This live air passes from the groove 26' (seeFig. 5) through a passage 27 in the valve chest and thence through apassage 28 in the said chest to a long passage 29 formed in the cylindercasing and communi cating by a port 30 with the forward extremity of thehammer chamber 31. This live air is sufiicient in quantity to cause thehammer to move rearwardly in the said chamber and the air in the rear ofthe hammer after the latter has passed port 18, exhausts through ports32 formed in the wall of the cylinder and communicating with passages 33leading to ports 34; which communicate with passages 35 formed'in theforward extremity o the valve chest'and .communicating with the centralchamber 24:

of the core, through ports 4 formed in the the chamber 24 this exhaustair passes through portsv 23 formed in the core to the space 22 andthence through a passage 37 formed in the valve chest, to exhaust portstremity of the valve chest. exhaust ceases, the live air whichconstantly valve,

The object of the double series 'ducts, the individual ducts of eachseries 'tion is a very important 38 and 39. communicating with theatmosphere.

The ports 32 are located some distance from the rear extremity of thehammer chamber and after the hammer has passed these ports the remainingair within the chamber cushions in the rear thereof and preventsthehammer from striking the ex- As soon as this acts on a relativelysmall circumferential shoulder 40 of the valve, acts to shift the latterrearwardly, thus opening the valve and allowing the live air or othermotive fluid to pass to the rear extremity of the hammer chamber, afterwhich the operation heretofore explained is repeated; 7

During the forward movement of the hammer the air forward of the latterexhausts through the port 30, the passages 29, 28 and 27 to the groove26, whence it travels through small ducts 11 into a groove 42 formed inthe valve chest and surrounding the and thence to the atmosphere throughthe ports 37, 38 and 39. When this occurs the small ducts 25 are closedat both extremities and .when the latter are. open to admit i live airto the forward extremity of the cylinder, as heretofore explained, thesmall ducts 41 have both extremities covered. These two series ofrelatively small ducts 25 and ll, one series serving to supply livemotive fluid to'the forward extremity of the cylinder to accomplish thereturn movement of the piston; and the other series serving to allow theair to exhaust from the forwardextremity of the cylinder during theforward movement of the piston, are an importantfeature of the valve,since both extremities of these small ducts are always covered when theyare inactive, thus producing a double check upon the entrance of the airto these ducts and preventing the wear of the valve du'e to the leakageof the air from adjacent ports or passages into the said ducts.

' It has been found in actual use that where recesses or ports are ofconsiderable size, and located adjacent grooves containing live air,that this air will gradually wear the steel of the valve sufliciently toallow the air to leak from one port or passageitmanother.

of small having both extremities closed when inactive,

is to overcome the aforesaid difficulty and obviate the wear of thevalve duev to the aforesaid cause.

The life of valves of the character in quesitem from a commercialstandpoint in motive fluid actuated drills and pneumatic tools of allkinds, my object is, as aforesaid, to'increase the life of this valve,and at the same time maintain its entire elficiency for the purposeintended.

and a I By the use of the core 10 passing through the hollow cylindricalvalve and forming a close tit therewith, the bearing surface of thevalve is more than doubled as compared with-valves of this class whoseexterior surface alone is engaged when m operation.

By virtue of this extensive bearing or wearing surface, the wear uponthe valve is correspondingly distributed wherebv it is so 'smaltupon anyparticular part that the life of the valveis greatly increased.

After the hammer has reached a position when'making its rearward strokewhereby the. exhaust ports 32 are closed against the escape of motivefluid from the rear extremity of the-cylinder, the exhaust port 43 isuncovered in the rear of the hammer communicating with a passage 44formed in the wall of the cylinder and in alinement with a passageformed in the valve chest, the latler being in ali'nement with a port 46formed in the disk 11 of the core 10. By reason of these'norts andpassages the motive fluid forward of the piston is quickly exhausted andthe air remaining in the rear extremity of the cylinder, cushions underthe pressure of the hammer and prevents the rear extremity of the latterfrom coming in direct contactwith the closure at the rear end of thecylinder.

The forward part of the valve-supporting core 10 is provided with anumber of small ducts 47 connecting the core chamber 24 with the groove15 of the chest, so that when the valve is open, (see Figs. 4 and 5) thelive air passes through these ducts into the chamber 24 and out throughthe ports 4 into the passages 34 and 33, and thence into the port 32.This occurs as soon as ,the valve is opened so that the chamber 24 andthe exhaust ports and passages forming a communication between theforward extremity of the said chamber and the rear extremity of thecylinder, are filled with motive'fiuid (see Figs. 4 and 5) the livemotive fluid enters the rear extremity of the cylinder through the port-12, the passage 13, grooves 14, 15 and 16, and passage 17, filling therear end'of the cylinder and acting upon the hammer 6 to drive thelatter forwardly against the striking pin 7. Just before the hammerreaches its forward limit of movement, the port 18 in the rear of thehammer is uncovered and the live air passes through said port into thepassages 19, 20 and 21, into the rear part of the space 22 in the rearof the valve and actingon the greater pressure area of the latter,drives the latter for-' I port 30 into the forward extremity of thecylinder, acting upon the hammer to drive the latter rearwardly. As thehammer moves rearwardly it closes the port 18 but the air or motivefluid in the rear of the cylinder exhausts freely through the ports 32,passages33 and 34, ports 4, core chamber 24, and port 36, into the space22 in the rear of the valve, and thence through passages 37 and 38 andport 39 to the atmosphere.

vAs the hammer continues its rearward travel,

it finally closes the ports 32, after which there being no escape forthe balance of the air in the rear extremity of the cylinder, this actsas a cushion upon the hammer to prevent the latter from striking theparts, closing the rear end of the cylinder cham-, her. As soon as theexhaust through the groove 22 in the rear of the valve is cut off by thehammer as aforesaid, the live motive fluid, acting upon the smallshoulder or reduced pressure area 40, serves to shift the valverearwardly, whereby the small angular ducts 41 have one extremitycommunicating with the groove 26, while their opposite extremitiescommunicate with the groove 42 whereby the motive fluid from the forwardextremity of the cylinder is exhausted through the port 30, passages 29,28 and 27, groove 26, ducts 41, and groove 42, which is in communicationwith the atmosphere through passages-37 and 38 and port 39.

Simultaneously with this exhaust from the I forward extremity of thecylinder, the live air passes through the small ducts 47 filling thecore chamber 24, the ports 4, the passages 34, 33 and the ports 32. timethe live air enters the rear extremity of the piston chamber through thepassages 17 and imparts the forward movement to the hammer, causing itto engage the striking pin as heretofore. explained. Before the hammerbegins its forward moveinent the motive fluid in the forward portion ofthe cylinder is exhausted through the port 43,

the passages 44 and 45 and the port 46 to the atmosphere.

The rear extremity of the valve chest is provided with a relativelysmall port 50, communicating at one extremity with the rear portion ofthe 'space 22 and at its opposite extremity with the exhaust port orpassage 38.. The object of this port 50 is to permit the escape of anylive air that,.may

leak into the rear extremity of the space 22,

At the same having a centrally located exhaust passage stantly exposedto the live ential pressure areas,

rocateforcoutrolling, the supply and ex.-

passing through with the valve chest, to form a support trolling themotive fluid supply to,

i and the larger of when the valveis open, thus preventing the possibleaccidental closure of the valve through'such leakage. The core 10 isrovided with small oilpassages 51 whose lnner extremities o'penon theexterior surface of the core upon which the valve is mounted, wherebythe bearing surfaces of the core and valve may be kept properlylubricated. I

Having thus described my invention, what I claim is: i v

' 1. The combination with a hammer cylin-' der and a motive fluidactuated hammer therein, ofa valve chest, a hollow cylindrical valvemounted to reciprocate therein, and a hollow core passing throughthevalve and fornnng a support therefor, the said core communicatingwith the rear extremity of the cylinder,.the forward end of the corebeing closed.

.2. The combination with a. hammer cylinder'and a motive fluid actuatedhammer therein, of a valve chest, ahollow, cylindrical valve, mounted toreciprocate therein, its opposite extremities being provided withdifferential pressure areas, and a hollow core the valve andcotiperating therefor, the core having a central exhaust passage and itsforward extremity being closed and flush with the surrounding surface ofthe rear end of the hammer cylinder.

3. The combination with a hammer cylinvalve chest and a valve having twoseries being arranged to be derand a motive fluid actuated pistontherein, of a hollow, cylindrical valve having differential pressureareas, one of which is con-. motive fluid,'and the other intermittentlyexposed thereto, and a hollow core passing through the valve andcooperating with the valve chest to form asupport therefor, whereby anextensive wearing surface is provided for the valve, the hollow of thecore forming an exhaust passage while the forward extremity of the coreis closed.

4:. The combination with a hammer cylin der and a motive fluid actuatedhammer therein, of a hollow, cylindrical valve for conand ex-,haust'from the cylinder, the said valve being mounted to reciprocate andhaving diflerthe smaller of which is constantly exposed to the livemotive fluid which is intermittently exhollow core forming a support forthe valve, and through which the exhaust from the rear extremity of thecylinder passes, the forward end of the said core being closed 5. Thecombination with a cylinder and a motive-fluid-actuated piston ,therein,of a hollow cylindrical valve mounted to recipposed thereto, and a wwith the live motive haust of the motive fluid, the valve ha ing aseries of relatively small ducts which when the valve is shifted in. onedirection,introduces live motive fluid to the forward ex- *tremity ofthe cylinder, and another series '1 when the valve .is shifted in onedirection;

and, the other series of ducts being in communication with the forwardextremity of the cylinder and with the atmosphere for exhaust purposeswhen the valve is shifted in the opposite direction.

7 The combination with a cylinder and a motive-fluid'actuated pistontherein, of a hollowcylindrical valve mounted to reciprocate therein,the said of relatively small passages, the one series in communicationwith the live motive fluid and the forward extremity of the cylinderwhen the valve is shifted in one direction; and the other series beingin communication with the exhaust and with the forward extremity of thecylinder when the valve is shifted in the opposite direction, bothextremities of. the individual ducts of each series being covered whenthe ducts are inactive. v

8. The combination with a cylinder and a motive-fluid-actuated pistontherein, of a v'alve chest, a hollow cylindrical valve mounted toreciprocate therein, said valve having. two series of ducts, theindividual ducts of each series havin both extremities exposed on theouter surface of the valve, one series of. ducts being in communicationfluid and the forward extremity of the. cylinder when the valve isshifted in one direction; and the other series of ducts being incommunication with the exhaust and the forward extremity of the cylinderwhen the valve is shifted'in the 'opposite direction, one always closedwhen the other series is in use for the passage of motive-fluid,eachseries of ducts having both extremities'of each duct covered'whenthe ducts are closed.

" 9; The combination with a cylinder, a motive fluid actuated piston,therein, and a tool in alinement with the piston, cylindrical valve,mounted to reciprocate for automatically regulating the supply andexhaust of the motive fluid, and a hollow interior support for the valvethrough which series of ducts being ofa hollow,

the exhaust from the rear extremity of the cylinder passes, the forwardextremity of the'said support being closed.

10. The combination of a hammer cylinder and a motive fluid hammertherein of a hollow, cylindrica valve located in the rear of thecylinder for controlling the supply and exhaust of the motive fluid, thecylinder having an exhaust port a short distance forward of itsrearextremity, the latter being otherwise closed against the escape ofmotive fluid, a hollow, cylindrical Valve mounted to reciprocate forregulating the supply and exhaust of themotive fluid, a hollow corecommunicating with the said cylinder exhaust port, the forward extremityof the core being closed and flush with the surrounding rear end wall ofthe hammer chamber.

11. The combination with a cylinder, a motive fluid actuated pistontherein and a tool in alinement with the piston, of a hollow,cylindrical valve for controlling the supply and exhaust of motivefluid, the said valve being mounted to reciprocate, and a hollowsupporting core passing through the 'valve, the chamber of the corebeing closed at its forward end and in communication with the rearextremity of the cylinder for exhaust purposes by means of an angularpassage. I

12. The combination with a cylinder, a motive fluid actuated pistontherein, and a tool in alinement'with the piston, of a hollowcylindrical valve mounted to reciprocate for regulating the supply andexhaust of motive fluid, and a hollow supporting core passing throughthe valve, the chamber of the core being closed at its forward extremityand in communication with the rear extremity of the cylinder byan-an'gular passage, and with the atmosphere for exhaust purposes, whenthe valve is in the closed pos1t1on. 13. The combinationof a cylinder, amotive-fluid-actuated piston therein, a hollow cylindrical valve mountedto reciprocate, a v

hollow core passing throu h the valve and forming a support there or,the cylinder having exhaust ports located a shortdistance forward of itsrearextremity, said ports beingin communication by'suitable.

passages, with the chamber of thecore, and

small ports formed in the core, and in com-.

munication withthe live motive fluidwhen the valve is open, for-fillingthe core chamber and the passages between said chamber the individualducts of both series having both extremities exposed on the' exterior'surfaces of the valve, and closed when not in use.

15. A hollow cylindrical valve having differential pressure areas at itsopposite extremities, and two series of relatlvely small longitudinallydisposed ducts located intermediate its extremities, each duct of eachseries having both extremities ope on the exterior surface of the valveand closed when not in use, substantially as described.

16. A hollow cylindrical valve having differential pressure areas at itsopposite extremities and two series of relatively small ducts located,intermediate its extremities and arranged in staggered relation, theindividual ducts of both-series having both extremities exposed .on theexterior surfaces of the valve, and-closed when not in use.

In'testimony whereof. I aflix my signature in presence of two witnesses.

ToM PUNsHoN, J r., J Essm F. HOBART.

